Nanoribbons channel light

In theory, computer chips that use light
rather than electricity to pass signals through circuits would be considerably
faster than today's electronics.

One challenge in making optical computer chips is finding a way
to guide light through minuscule channels between circuits.

Researchers from the University of California at Berkeley and
Lawrence Berkeley National Laboratory have made crystalline oxide nanoribbons
that are capable of carrying light and that are flexible enough to form
the patterns needed to carry out logic operations.

The nanoribbons could eventually be used to carry out chip-based
optical computing and to enable tiny chemical and biological sensors.

The nanoribbons range from 15 to 2,000 nanometers wide by 5 to
1,000 nanometers thick and are as long as 1.5 millimeters. Nanoribbons
that are several hundred nanometers wide are capable of channeling visible
and ultraviolet light even though they are narrower than the wavelengths
of the light. A nanometer is one millionth of a millimeter.

The researchers also found that the ribbons do not need to be
connected end-to-end in order to transmit light from one to another. They
found that the most efficient way to connect nanoribbons was simply overlapping
two ends. Molecular electrostatic forces held the ends together.

The researchers have also coupled one of the nanoribbons to a
light-emitting nanowire. There are working on coupling nanoribbons with
nanowire lasers and photodetectors.

Nanowire photonic circuitry could be used practically in 10 years,
according to the researchers. The work appeared in the August 26, 2004
issue of Science.